Helleborus plant named ‘COSEH 760’

ABSTRACT

A new and distinct cultivar of  Helleborus  plant named ‘COSEH 760’, characterized by its upright and somewhat outwardly arching plant habit; uniform and freely flowering habit; dark green-colored leaves; long flowering period; single light green and white bi-colored flowers; and good garden performance.

Botanical designation: Helleborus×nigercors.

Cultivar denomination: ‘COSEH 760’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Helleborus plant, botanically known as Helleborus×nigercors, and hereinafter referred to by the name ‘COSEH 760’.

The new Helleborus plant is a product of a planned breeding program in Glandorf, Germany. The objective of the breeding program was to create new uniform Helleborus plants with unique and attractive leaf and flower coloration and resistance to pests.

The new Helleborus plant originated from a cross-pollination conducted by the Inventor in Glandorf, Germany in November, 2002 of two unnamed proprietary seedling selections of Helleborus×nigercors, not patented. The new Helleborus plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination grown in a controlled greenhouse environment in Glandorf, Germany in February, 2005.

Asexual reproduction of the new Helleborus plant by divisions in a controlled greenhouse environment in Glandorf, Germany since March, 2005, has shown that the unique features of this new Helleborus plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Helleborus have not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in cultural practices and environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of the Helleborus ‘COSEH 760’. These characteristics in combination distinguish the Helleborus ‘COSEH 760’ as a new and distinct Helleborus plant:

-   -   1. Upright and somewhat outwardly arching plant habit.     -   2. Uniform and freely flowering habit.     -   3. Dark green-colored leaves.     -   4. Long flowering period.     -   5. Single light green and white bi-colored flowers.     -   6. Good garden performance.

Compared to plants of the parent selections, plants of the new Helleborus flower more freely and more uniformly.

Plants of the new Helleborus can be compared to plants of Helleborus niger×Helleborus lividus ‘COSEH 700’, disclosed in U.S. Plant Pat. No. 21,003. Plants of the new Helleborus differ primarily from plants of ‘COSEH 700’ in the following characteristics:

-   -   1. Plants of the new Helleborus have lighter green-colored         leaves than plants of ‘COSEH 700’.     -   2. Plants of the new Helleborus have smaller flowers than plants         of ‘COSEH 700’.     -   3. Plants of the new Helleborus and ‘COSEH 700’ differ in flower         color.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the overall appearance of the new Helleborus plant and show the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Helleborus plant.

The photograph on the first sheet comprises a side perspective view of a typical flowering plant of ‘COSEH 760’ grown in a container.

The photograph on the second sheet is a close-up view of a typical flower of ‘COSEH 760’.

DETAILED BOTANICAL DESCRIPTION

The aforementioned photographs and following observations, measurements and values describe plants grown during the winter in 1.5-liter containers in a glass-covered greenhouse in Glandorf, Germany and under conditions which closely approximate commercial Helleborus production. During the production of the plants, day temperatures ranged from 12° C. to 32° C. and night temperatures ranged from 3° C. to 18° C. Plants were one year old when the photographs and the description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2007 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical classification: Helleborus×nigercors ‘COSEH 760’. -   Parentage:     -   -   Female, or seed, parent.—Unnamed proprietary seedling             selection of Helleborus×nigercors, not patented.         -   Male, or pollen, parent.—Unnamed proprietary seedling             selection of Helleborus×nigercors, not patented. -   Propagation:     -   -   Type.—By tissue culture.         -   Time to initiate roots.—About two months at 12° C.         -   Time to produce a rooted young plant.—About six months at             4° C. to 15° C.         -   Root description.—Thick to thin, fleshy; white to brown in             color.         -   Rooting habit.—Sparse. -   Plant description:     -   -   Plant form and growth habit.—Herbaceous perennial; upright             and somewhat outwardly arching plant habit with flowers held             above the foliar plane; shape, globular; moderately vigorous             growth habit.         -   Plant height.—About 26.2 cm.         -   Plant diameter (area of spread).—About 38.5 cm. -   Foliage description:     -   -   Arrangement.—Leaves arranged in a basal rosette; leaves             palmately compound with five leaflets per leaf.         -   Leaf length.—About 16 cm.         -   Leaf width.—About 20 cm.         -   Leaflet length.—About 10.9 cm.         -   Leaflet width.—About 4 cm.         -   Leaf shape.—Palmate; orbicular in outline.         -   Leaflet shape.—Elliptic to ovate; lower leaves occasionally             cleft.         -   Leaflet apex.—Acute.         -   Leaflet base.—Attenuate.         -   Leaflet margin.—Sharply serrate.         -   Leaflet texture, upper and lower surfaces.—Smooth, glabrous;             leathery.         -   Leaflet venation pattern.—Pinnate.         -   Leaflet color.—Developing leaves, upper surface: Close to             137C. Developing leaves, lower surface: Close to 146B. Fully             developed leaves, upper surface: Darker than 147A; venation,             close to 144B. Fully developed leaves, lower surface: Close             to 147B; venation, between 144C and 145A.         -   Petiole.—Length: About 8.2 cm. Diameter: About 6 mm.             Texture, upper and lower surfaces: Smooth, glabrous. Color,             upper and lower surfaces: Close to 144A to 144B. -   Flower description:     -   -   Flower shape and habit.—Single rotate flowers arranged on             terminal cymes; freely and uniform flowering habit with             about 110 flowers and flower buds per plant; flowers facing             outwardly to slightly nodding.         -   Fragrance.—None detected.         -   Natural flowering season.—Long flowering period; plants             flower from late winter to early spring in Germany.         -   Flower longevity on the plant.—About ten days; flowers not             persistent.         -   Flower buds.—Length: About 1.7 cm. Diameter: About 1 cm.             Shape: Ovate. Color: Close to 145C.         -   Inflorescence height.—About 21.2 cm.         -   Inflorescence diameter.—About 16.6 cm.         -   Flower diameter.—About 6 cm.         -   Flower depth (height).—About 2.7 cm.         -   Petals.—Transformed into nectaries.         -   Sepals.—Arrangement: About five in a single whorl. Length:             About 2.9 cm. Width: About 1.8 cm. Shape: Ovate to elliptic.             Apex: Obtuse. Margin: Entire. Texture, upper and lower             surfaces: Smooth, glabrous. Color: When opening, upper and             lower surfaces: Close to 145C and towards the base, close to             145A. Fully opened, upper surface: Close to 145C to 145D,             towards the margins, close to 157A and towards the base,             close to 145A; with development, color becoming closer to             138A. Fully opened, lower surface: Close to 145A to 145B,             towards the margins, close to 157A and towards the base,             close to 144B to 144C.         -   Peduncles.—Strength: Moderately strong. Length: About 5 cm.             Diameter: About 6.5 mm. Aspect: About 15° from vertical.             Texture: Smooth, glabrous. Color: Close to 144B to 144C and             towards the base, close to 178A to 178B.         -   Pedicels.—Strength: Moderately strong. Length: About 3.5 cm.             Diameter: About 2 mm. Aspect: About 10° from the peduncle             axis. Texture: Smooth, glabrous. Color: Close to 145B.         -   Reproductive organs.—Stamens: Quantity per flower: About 70.             Filament length: About 1.4 cm. Filament color: Close to             157D. Anther shape: Narrowly reniform. Anther length: About             2 mm. Anther color: Close to 154B. Pollen amount: Scarce.             Pollen color: Close to 158D. Pistils: Quantity per flower:             About five. Pistil length: About 1.2 cm. Stigma shape:             Club-shaped. Stigma color: Close to 150C to 150D. Style             length: About 1.1 cm. Style color: Close to 145A to 145B.             Ovary color: Close to 144B. Nectaries (transformed petals):             Quantity per flower: About 14. Length: About 7 mm. Diameter,             apex: Close to 1.5 mm. Diameter, base: Close to 1 mm. Shape:             Flattened triangular. Color: Close to 145A and towards the             apex, close to 150B.         -   Seeds/fruits.—Seed and fruit development have not been             observed. -   Garden performance: Plants of the new Helleborus have been observed     to have good garden performance and to tolerate rain, wind and     temperatures ranging from about −10° C. to about 35° C. -   Pathogen/pest resistance: Plants of the new Helleborus have not been     shown to be resistant to pathogens and pests common to Helleborus. 

1. A new and distinct Helleborus plant named ‘COSEH 760’ as illustrated and described. 